The present invention relates to a needle guide for a medical imaging instrument. More particularly, the invention is directed to an apparatus and method for guiding needles into selected locations of a patient relative to a medical instrument imaging sensor. The needle guide facilitates entry of a needle into a human or animal body.
Imaging instruments, such as ultrasound probes, have revolutionized the manner in which many important medical procedures are performed. These medical instruments utilize substantially non-invasive imaging techniques to explore and assess the condition of human tissue. As a result of these non-invasive imaging techniques, diagnostic and therapeutic protocol""s have been developed that allow many highly successful and safe procedures to be performed with a minimum of disturbance to patients.
Ultrasound and other imaging techniques have received widespread acceptance as a useful diagnostic tool. Ultrasound is particularly well suited for obstetrics, where real-time scanners create a continuous image of a moving fetus that can be displayed on a monitoring screen. The image is created by emission of very high frequency sound waves from a transducer placed in contact with the mother""s skin. Repeated arrays of ultrasonic beams scan the fetus and are reflected back to the transducer, where the beams are received and the data transmitted to a processing device. The processing device analyzes the information and composes a picture for display on the monitoring screen. Relative measurements may be made, and the gestational age, size and growth of the fetus can be determined. In some circumstances, a needle is guided into amniotic fluid in order to retrieve a fluid sample for analysis. These samples can be useful for diagnosing irregular conditions and can indicate that prenatal care is necessary for the fetus. Ultrasound probes, and other imaging instruments, are also used for a variety of other purposes, such as identifying the existence, location, and size of tumors, as well as the existence of other medical conditions, including the atrophy or hypertrophy of bodily organs.
Increasingly, imaging instruments have been used to explore cavities of humans and animals in order to conduct routine examinations, as well as to identify evidence of illness. These endocavities, such as those associated with the human digestive and reproductive tracts, can be the location of benign and malignant tumors. Using ultrasound, these tumors can be located and assessed. It is frequently desirable and even essential that biopsy samples of the tissue or fluid of a suspected tumor be removed for analysis. Biopsy samples may be taken by carefully directing a hand-held needle, such as a biopsy instrument, catheter, or other thin instrument (hereafter generalized as xe2x80x9cneedlexe2x80x9d or xe2x80x9cneedlesxe2x80x9d) into the body of a patient in order to remove a tissue sample. It is normally desirable that the needle be guided to a specific position within the body. Unfortunately, such hand-held direction of a needle is often inadequatexe2x80x94being both inaccurate and time consuming.
Various guide devices have been designed for assisting in directing needles during imaging analysis. Unfortunately, most of these devices are ill-suited for use in an endocavity. For example, U.S. Pat. Nos. 5,623,931 to Wung and 5,076,279 to Arenson are directed to needle guides for use with ultrasound imaging systems. However, neither of these needle guides is readily adaptable for insertion into an endocavity. Certain efforts have been made to devise a needle guide for insertion into endocavities, but these efforts have been of rather limited success. For example, U.S. Pat. No. 4,911,173 to Terwilliger describes a biopsy attachment for an ultrasound probe, but this biopsy attachment is complicated and cumbersome to use. Similarly, U.S. Pat. No. 5,235,987 to Wolfe teaches a needle guide for use with an imaging probe, but the needle guide does not permit the easy removal of the needle from the probe while the probe is still within the patient, nor does it allow different size needles to be used with the same needle guide.
Another specific problem with many current needle guide systems is that they are not well suited to use with a sterile cover, such as a latex film, placed over the imaging instrument. Such covers are increasingly desirable in order to maintain the ultrasound sensor in a sterile environment. The covers reduce the likelihood of contamination between patients and reduce the cost of medical procedures by minimizing sterilization costs. One challenge of working with latex and similar polymer based covers is that they have a high coefficient of friction and are subject to binding when in contact with moving pieces of an imaging sensor or needle guide. Such binding can lead to tears or punctures of the cover. For example, some prior art imaging sensors have removable pieces that are frictionally fit over a latex cover. Such designs are problematic because they can be difficult to fit and remove, as well as cause problems with binding and an ensuing risk of tearing.
Consequently, a need exists for an improved needle guide system that will allow a needle to be easily inserted and removed from a patient undergoing imaging analysis of a bodily cavity, with a minimum of discomfort to the patient. Such needle guide system should allow the needle to easily and effectively obtain a biopsy sample from a precise location within a patient. It is further desirable that the needle guide system permit the use of a sterile cover over the imaging instrument in order to reduce sterilization costs, as well as to improve hygiene.
The present invention is directed to a needle guide system for use in guiding a needle or other instrument into a patient who is undergoing imaging analysis. In specific implementations of the invention, the needle guide includes a body configured for insertion into a cavity, a slot in the body configured to receive a needle shaft, and a retaining member configured and arranged to secure the needle within the slot. The retainer member is optionally designed to be removably placed within the slot. In a particular implementation, the slot in the body has an exit for the needle, the exit configured and arranged proximate a sensor of an imaging instrument when the needle guide system is secured to the imaging instrument.
The body of the needle guide optionally has a first surface configured for securing to an imaging instrument, the first surface substantially in contact with the imaging instrument when in use. A second surface of the needle guide is exposed to the cavity and is substantially smooth and free of obstructions.
In addition, the retainer member is configured and arranged in certain implementations to be rotated within the slot such that the retainer member may assume a first position in which a needle may be removed or inserted into the slot; and a second position in which the needle is secured within the slot. Alternatively, the retainer member is configured and arranged to slide along the slot in the body, wherein an interior cross-sectional area of the slot changes as the retainer member slides along the slot in the body. In this manner, the interior cross-sectional area is changeable to accommodate needle shafts of different diameters.
In certain implementations, the body is integrally formed to an imaging instrument. Alternatively, the body is configured and arranged to be removably secured to an imaging instrument. Also, the body may be constructed for insertion over a sterile barrier. The body may include an exterior surface conforming substantially to the profile of the imaging instrument. The slot within the body may be curved to direct the end of a flexible needle or other instrument into the imaging field of an imaging instrument.
The needle guide allows the release of the needle in a manner that the needle guide and imaging instrument may be removed from the patient without removal of the needle. Such implementations are useful, for example, to drain portions of tumors, cysts, etc. within a human or animal body.
The present invention is further directed to a method for securing and directing a needle or other instrument during imaging analysis. The method includes providing a needle and a needle guide. The needle guide has a body configured for insertion into a cavity, a slot in the body configured to receive a needle shaft, and a retaining member configured and arranged to secure the needle within the slot. The needle is inserted into the needle guide, and at least a portion of the needle guide is inserted into a cavity of a patient. In specific implementations of the method, the needle guide further includes a slot in the body comprising an exit for the needle, the exit configured and arranged proximate a sensor of an imaging instrument when the needle guide system is secured to the imaging instrument. Also, the retainer member of the method may be configured and arranged to be rotated within the slot such that the retainer member may assume a first position in which a needle may be removed or inserted into the slot, and a second position in which the needle is secured within the slot.
As used herein, the term xe2x80x9cneedlexe2x80x9d includes various long thin medical instruments, including various probes, sampling devices, and therapeutic instruments.
The above summary of the present invention is not intended to describe each discussed embodiment of the present invention. This is the purpose of the figures and the detailed description which follow.
Other aspects and advantages of the invention will become apparent upon reading the following detailed description and references to the drawings, in which:
FIG. 1 is a side elevational view of a needle guide constructed and arranged in accordance with the present invention, the needle guide shown attached to the exterior of an imaging probe.
FIG. 2 is a side elevational view of the needle guide shown in FIG. 1, further showing a needle inserted into the needle guide and depicting the plane of the imaging probe as cross sectional line A-Axe2x80x2.
FIG. 3 is a side elevational view of a needle guide constructed and arranged in accordance with the present invention, the needle guide shown removed from an imaging probe.
FIG. 4 is a perspective view of a needle guide constructed and arranged according to the present invention, showing a needle retainer member removed from the body of the needle guide.
FIG. 5A is a cross-sectional view of a needle guide constructed and arranged in accordance with the present invention, taken along lines D-Dxe2x80x2 of FIG. 3, showing the needle retainer positioned in an xe2x80x9copenxe2x80x9d manner such that a needle can be laterally inserted into, or removed from, the needle guide.
FIG. 5B is a cross-sectional view of a needle guide constructed and arranged in accordance with the present invention, showing the needle retainer positioned in a xe2x80x9cclosedxe2x80x9d manner such that a needle is retained along its shaft within the needle guide.
FIG. 6A is a perspective view of another implementation of a needle guide in accordance with the present invention.
FIG. 6B is a perspective view of the needle retainer for the needle guide shown in FIG. 6A.